JPH0781023B2 - Method of making abrasion resistant polycarbonate articles - Google Patents

Description

FIELD OF THE INVENTION The present invention relates generally to polycarbonate articles,
In particular, it relates to polycarbonate articles that exhibit improved abrasion resistance.

Prior Art Polycarbonate resins are well known, commercially available materials with physical and chemical properties useful in a wide range of applications. Polycarbonate exhibits excellent breakage resistance, so
It has been used as a replacement for glass in many products such as automotive headlight and brake light lenses, window safety glass, architectural clear glazing and the like. However, the main drawbacks exhibited by polycarbonates are their very low scratch resistance and their sensitivity to UV-induced degradation.

A method of improving the scratch resistance of thermoplastics such as polycarbonate has included the step of providing an inorganic protective layer on the surface of the polycarbonate. For example, Kaga
Nowicz, U.S. Pat. No. 4,328,646, discloses the formation of wear resistant articles by glow discharge treating a mixture of hard coating precursors and depositing the product directly onto a plastic substrate as an extremely thin film. Is disclosed. However, since there is no intermediate layer between the substrate and the hard coating layer, the article is subjected to various heating / heating.
Surfaces often crack when exposed to cooling cycles.

Hall et al., U.S. Pat. No. 4,200,681, describes depositing a glass (SiO ₂ ) surface layer by vapor deposition on an intermediate primer layer deposited on the surface of a polycarbonate substrate. However, vapor deposition techniques for applying layers of SiO ₂ are often undesirable for several reasons. For example, individual particles of SiO ₂ can condense on the coated surface after evaporation at a rate that varies with individual specific deposition sites, often providing a non-uniform glass surface with pits, pinholes and other defects. Moreover, this technique generally only allows line-of-sight deposition, thus resulting in undesired variations in the thickness of the glass coating applied to curved or indented surfaces. Moreover, vapor deposition processes similar to those of Hall et al. Do not produce reactive film-forming species that can react with the underlying surface to form a highly adherent coating. These processes also require extremely low operating temperatures, which are often difficult to maintain during the deposition process, and lead to undesired outgassing of the polycarbonate.

Geffcken et al U.S. Pat. No. 3,713,869 describes a method of depositing an interlayer polymerized by glow discharge on a polycarbonate surface. On this intermediate layer, a hard inorganic layer is then deposited by an electron beam gun in the same way as used by Hall et al., Leading to the same drawbacks mentioned above.

Accordingly, there has been much interest in and continued research into improved processes for the production of abrasion resistant polycarbonate articles having higher abrasion resistance, yet improved in various other physical properties. There is.

Accordingly, one object of the present invention is to provide a method of making polycarbonate articles having a high degree of abrasion resistance.

Another object of the present invention is to provide an improved method of applying a smooth, hard transparent layer of uniform thickness on a polycarbonate substrate.

Yet another object of the present invention is to provide an abrasion resistant polycarbonate article having a uniform thickness, highly abrasion resistant and having a surface layer deposited which is free of pinholes and microcracks.

SUMMARY OF THE INVENTION In accordance with the present invention, an object of the above is to provide an improved process for producing an abrasion resistant plastic article having a polycarbonate substrate; an interfacial layer comprising an adhesive resinous composition on the substrate; and an abrasion resistant surface layer. Achieved by discovery. The improved method according to the present invention comprises the following steps; (a) a step of applying an interface layer to the surface of the substrate (which may or may not be undercoated); and (b) enhancement by plasma on the interface layer. The step of applying the surface layer by the chemical vapor deposition method (hereinafter, also referred to as PECVD) described above.

The interface layer of the present invention can be formed from a variety of materials and can be applied to the substrate by coating means. Alternatively, the interfacial layer can be applied to the substrate by PECVD as detailed below.

The wear resistant surface layer can be composed of a wide range of materials as detailed below.

Broadly speaking, the term PECVD as used herein
(Plasma-enhanced chemical vapor deposition) places a substrate in a reaction chamber; and then delivers at least one gaseous reactant capable of forming the desired layer to the reaction chamber in a laminar flow with respect to the coated surface. And an electric field at a suitable pressure to form a plasma in the reactants. These gaseous reactants react in the plasma and on the coated surface to form the desired layer. As used herein, the terms "surface", "coated surface" or "deposition surface", unless otherwise indicated, refer to the substrate surface or subbing surface when applying an interfacial layer and to the interface when applying a surface layer. It should be understood that it refers to the layer surface.

By using the method of the present invention, a polycarbonate article is obtained that has all of the typical properties of a polycarbonate, such as high tensile strength and high impact strength, yet exhibits excellent abrasion resistance. Furthermore, the presence of an interfacial layer between the abrasion resistant surface layer and the polycarbonate substrate provides a high degree of adhesion between the surface layer and the substrate.

Further, unlike conventional vapor deposition methods that require high operating temperatures, and therefore often have a detrimental effect on polycarbonate materials, PECVD can be performed at temperatures that are harmless to polycarbonate as disclosed herein. it can. The term "conventional" vapor deposition method as used herein refers to coating material precursors in the gas phase at elevated temperatures, typically 40
It means both the CVD method of reacting at temperatures above 0 ° C. and the “physical vapor deposition method” of simply depositing a preformed coating composition on a substrate. These methods do not involve the use of plasma.

DETAILED DISCLOSURE OF THE INVENTION The article formed by the method of the present invention comprises a polycarbonate substrate. Polycarbonate materials suitable for making such substrates are well known to those skilled in the art and are described, for example, in US Pat. Nos. 4,200,681 and 4,200,681, which are incorporated herein by reference.
4,210,699. Such polycarbonates generally have the formula: Where R is a divalent group of a dihydric phenol, such as a divalent group from 2,2-bis (4-hydroxyphenyl) -propane, also known as bisphenol A, Is a repeating unit.

Polycarbonates within the scope of the present invention can be made by several well known methods. For example, the production of polycarbonate may be accomplished by reacting a dihydric phenol with a carbonate precursor. A wide range of dihydric phenols, such as bisphenol A, can be used in the present invention. Many dihydric phenols are incorporated herein by reference, U.S. Pat. Nos. 2,999,835 and 3,083.
No. 2,365, No. 3,160,121, No. 3,334,154 and No. 3
No. 4,190,681. A large number of carbonate precursors can be used, typical of which are either carbonyl halides, carbonate esters or haloformates. Examples of carbonate precursors are described in US Pat. No. 4,190,681.

The polycarbonate substrate may be molded into various shapes depending on the intended end use for the carbonate article. For example, a polycarbonate film substrate may be formed by casting the molten polymer onto a flat open mold and then pressing the material to a uniform thickness. After cooling, the film can then be provided with an interfacial layer thereon, as further described below. In addition, the polycarbonate substrate can also be in the form of tubes, rods or irregularly shaped objects. When the article of the invention is used as a glass material, the polycarbonate material can be formed into flat or curved sheets by well known methods such as extrusion or injection molding.

As previously mentioned, the interfacial layer is applied on the surface of the polycarbonate substrate by the method of the present invention. The term "interfacial layer" as used herein defines the layer of adhesive resinous composition disposed between the surface layer of the present invention and the substrate. The surface of the interface layer is in contact with the subsequently applied surface layer. The opposite surface of the interface layer is either in contact or not in contact with the opposing surface of the substrate, depending on whether an undercoat layer is present on the substrate surface, as described further below.

The composition of the interface layer of the present invention relates both to the end use intended for the polycarbonate article and to the method for applying the interface layer onto the polycarbonate substrate.

One of the important functions of the interfacial layer in the preferred embodiment of the present invention is to act as an introduction site for one or more ultraviolet (UV) absorbers. By concentrating such an absorber in a relatively thin interfacial layer, the underlying polycarbonate is protected from UV radiation more efficiently than if the absorber were dispersed throughout the polycarbonate itself.

Organosilicones are particularly useful materials for interface layer formation. The term "organosilicon" is used herein to include organic compounds in which at least one silicon atom is bound to at least one carbon atom, and silicone materials and usually silanes, siloxanes. Includes materials referred to as classes, silazanes and organosilicones. Suitable organosilicones for the methods and articles of the present invention are C. Eaborn, Organosili.
con Compounds, 1960 Butterworths Scientific Public
Published by ations. Other suitable organosilicon compounds are described by K. Saunders, Organic Polymer Chemis.
try, published by Chapman ad Hall Ltd., 1973.

Non-limiting examples of organosilicon compositions useful for the present invention have the general formula: R ⁷ _n SiZ _{(4-n) where} R ⁷ is a monovalent hydrocarbon group or a halogenated monovalent hydrocarbon group. Z is a hydrolyzable group and n may be a number from 0 to 2) and is a partial hydrolysis and condensation product of the compound represented by More specifically, Z is preferably a group such as a halogen, alkoxy, acyloxy or aryloxy group. Such compounds are well known to those skilled in the art and are described, for example, in US Pat. No. 4,224,378 to S. Schroeter et al., Which is incorporated herein by reference.

Other representative organosilicons within the scope of the present invention have the formula: R ⁸ Si (OH) _{3 where} R ⁸ is an alkyl group containing from about 1 to about 3 carbon atoms, a vinyl group, 3, 3,3-trifluoropropyl group, γ-
A silanol having a glycidoxypropyl group and a γ-methacryloxypropyl group) (at least about 70% by weight of the silanol is CH ₃ Si (OH)).
₃ )). Such compounds are described in US Pat. No. 4,242,381, which is incorporated herein by reference.

Preferred organosilicon compounds for the present invention where the interfacial layer is to be applied by PECVD as described below are hexamethyldisilazane, hexamethyldisiloxane vinyltrimethylsilane and octamethylcyclotetrasiloxane. Monomer vapors of these compounds polymerize in plasma to form an interface layer. This point will be described later.

If it is desired that the organosilicon-based interfacial layer have a higher hardness, the organosilicon material can contain colloidal silica dispersed therein. Dispersions of colloidal silica in organosilicon materials are well known to those skilled in the art and are described, for example, in U.S. Pat.Nos. 3,986,997, 4,027,073, 4,239, which are incorporated herein by reference.
No. 798, No. 4,284,685 and No. 4,436,851. Colloidal silica is typically dispersed in an aqueous solution of organosilicon. For example, these compounds are lower aliphatic (eg having less than about 6 carbon atoms) alcohols of silanol partial condensates.
It can consist of a dispersion of colloidal silica in an aqueous solution.

If colloidal silica is used, it should comprise from about 5% to about 70% of the total nonvolatile weight of the interfacial layer. Further, the aqueous colloidal silica dispersions used in this invention generally have a particle size in the range of about 5 to about 150 nm (nanometers) in diameter. A particularly preferred particle size range is about 5 in diameter.
~ About 30 nm.

A particularly preferred colloidal silica-containing organosilicon material for use as an interfacial layer is described in B. Ashby et al., U.S. Pat. No. 4,374,674, which is incorporated herein by reference, which comprises the following components: ) Formula RSi (O in a mixture of aliphatic alcohol and water
H) ₃ or R ₂ Si (OH) ₂ (wherein R is a group selected from the group consisting of an alkyl group having about 1 to 3 carbon atoms and an aryl group having about 6 to 20 carbon atoms). Silanol having a certain amount (but at least 70% by weight of the silanol is CH
A partial condensate of ₃ Si (OH) ₃ or (CH ₃ ) ₂ Si (OH) ₂ ) in a solution of a colloidal silica dispersion (wherein the dispersion is
Includes 10 to 50% by weight of solids, said solids being 10 to 70% by weight
Consisting essentially of colloidal silica of 0 to 90% by weight) and a formula (b). (In the formula, X is> C = O or Y is H or OH; Z is H, OH, OQ or OW, but when Y is H, at least one Z is OH; and Q is --CH ₂ (CH ₂ ) _N Si (R ² ) _x OR ¹ ) _y ;; W is −C _m H
_{2m + 1} ; x = 0, 1 or 2, y = 1, 2 or 3, x +
y = 3; R ¹ is an alkyl or alkanoyl group having about 1 to 6 carbon atoms; R ² is an alkyl group having about 1 to 6 carbon atoms; n = 0, 1 Or 2 and m =
1 to 18)). The composition comprising this material typically contains an amount of acid sufficient to provide a pH in the range of about 3.0 to 7.0. The aforementioned Ashby et al. Patent also describes methods of applying and curing these coatings.

Representative condensates of R ₂ Si (OH) ₂ type silanols and compositions formed therefrom are disclosed in US Pat. No. 4,159,206, incorporated herein by reference.

Another preferred organosilicon material for use as an interfacial layer consists of ammonium hydroxide-stabilized colloidal silica and a water / aliphatic alcohol dispersion of a partial condensate derived from an organotrialkoxysilane. Such substances are referred to herein by B. Anth.
ony U.S. Pat.No. 4,624,870 and preferably has an alkaline pH, i.e. at least about 7.1.
Used at a pH of.

Organosilicon materials, including colloidal silica, are not typically applied by PECVD, but are conventionally coated on a substrate as described below. In another embodiment, the surface layer formed by the method of the present invention contains an acrylic substance, that is, a thermoplastic or thermosetting acrylic polymer as the adhesive resinous composition. The term "acrylic" as used herein includes a compound containing an acrylic functional group together with a molecular group. An example of this type of acrylic material is the acryloxy-functional silane described below.

An example of an acrylic material is ultraviolet (UV) curable. These materials are typically applied to the substrate as a monomer, polycarbonate. One preferred composition of this type has the following components: (A) General formula: (In the formula, n is an integer having a value of 1 to 4; R ³ is an aliphatic hydrocarbon group, an aliphatic hydrocarbon group having at least one ether bond, and a substituted fat having at least one ether bond. A group selected from the group consisting of group hydrocarbon groups;
And R'is hydrogen or a lower alkyl group), at least one polyfunctional acrylate monomer represented by: (B) colloidal silica; (C) formula: (In the formula, R ⁴ is a monovalent hydrocarbon group; R ⁵ is a divalent hydrocarbon group; R ⁶ is a hydrogen atom or a monovalent hydrocarbon group; x is an integer of 1 to 4) At least one acryloxy-functional silane; and (D) a photochemical reaction initiator.

After applying such a composition to a substrate, it is irradiated with UV light for a time sufficient to polymerize and crosslink the polyfunctional acrylate monomer, thereby forming a cured coating. Ketones are useful as initiators when curing the acrylic composition in an inert atmosphere such as nitrogen, while at least one ketone and at least one amine when curing in an oxygen-containing atmosphere. The mixture is useful as an initiator. This is described in US Pat. No. 4,478,876 to R. Chung, which is hereby incorporated by reference.

UV curable materials are referenced herein by R. Ch.
It is described in detail in U.S. Pat. Nos. 4,486,504 and 4,372,835. A number of suitable UV-curable acrylic functional group containing materials are also disclosed in U.S. Pat. Nos. 4,455,205 and 4,455,205 to D. Olson et al., Which are also incorporated herein by reference.
No. 491,508. Suitable methods for the application and curing of these materials are described in more detail in the patent documents cited above.

Other thermosetting acrylic polymers suitable for the present invention are
Encyclopedia of Polymer Science and Technology, Volume 1 (Interscience Publishers, John Wiley and Sons,
Inc., 1964) and D. Solomon, Chemistry of Org
Anic Film Formers (John Wiley and Sons, Inc., 1967) and in each of the references cited above.
Further, US Pat. No. 4,242,383 also describes a suitable thermosetting acrylic polymer, and those descriptions are also incorporated herein.

As already mentioned, thermoplastic acrylics can also constitute the interface layer. Among the suitable thermoplastic acrylics are those that have been polymerized prior to coating on a substrate. An example of this type of acrylic material is one formed by polymerizing at least one monomer selected from the group consisting of acrylic acid esters and methacrylic acid esters. These and other suitable thermoplastic acrylics are described in more detail in US Pat. No. 4,239,798 to S. Schroeter et al., Incorporated herein by reference. Copolymers formed from acrylate or methacrylate monomers are also included within the meaning of the term "thermoplastic acrylic polymer" as used herein.

The acrylic composition forming the interface layer may further contain an ultraviolet absorber. Examples of such absorbents are of the hydroxybenzophenone and benzotriazole type, but other absorbents may also be used. The amount of UV absorber is related in part to the composition of the particular acrylic material and in part to whether the UV absorber is also present in the subbing layer and / or the substrate material itself.

Acrylic compositions can be applied by the PECVD method, as described below, when the reactant precursors are volatile. For example, the acrylic or methacrylic acid ester monomer can be vaporized and then plasma polymerized to deposit a polymer coating on the underlying coating surface underneath.

The interfacial layer may be composed of polyolefin in another embodiment. Non-limiting examples of suitable polyolefins include polyethylene, polypropylene, polyisoprene and copolymers of these types of materials. In addition, synthetic and natural elastomers are also included within the broad definition of the term "polyolefin" as used herein, and many of these elastomers are described in the Encyclopedia of Polrmer Scienc.
e and Technolgy, Vol. 5, pp. 406-482 (1966). Many of these materials may be deposited according to the present invention by vaporizing and then subjecting their monomeric precursors to plasma polymerization under the plasma conditions described below.

In the manufacture of the abrasion resistant article of the present invention, the interfacial layer may be applied to the surface of the substrate by conventional methods well known to those skilled in the art, such as spray coating, roll coating, curtain coating, dip coating and brush coating. . If the surface of the polycarbonate substrate is not primed, the interfacial layer material will be applied directly to the substrate surface (typically first cleaned and pretreated as described below). For example, the substrate surface may be coated with a further curable organopolysiloxane dissolved in an organic solvent solution, followed by evaporation of the volatile solvent in a known manner, followed by thermal curing of the organopolysiloxane on the polycarbonate. . Various other known coating methods are disclosed in US Pat. No. 3,983, incorporated herein by reference.
6,997 and 4,242,383.

As mentioned above, the surface of the substrate may be primed prior to applying the interface layer. This subbing layer tends to increase the adhesion of the interfacial layer to the polycarbonate substrate.

As long as various known materials for forming the subbing layer are compatible with both the polycarbonate and the interfacial layer material,
Can be used. Preferred undercoat materials are the thermoplastic and thermosetting acrylic polymers described above, but the undercoat materials generally have some compositional differences from the interfacial layer materials.

Details of forming a subbing material and its application are well known to those skilled in the art. For example, the acrylic composition is first water,
It may be formed by preparing an emulsion containing a hydroxy ether or alkanol, an acrylic polymer and other well known additives necessary for the end use of the particular article, eg UV absorbing compounds such as those mentioned above. After applying the mixture to the surface of the polycarbonate, water and a substantial portion of the hydroxyether or alkanol components are then evaporated. The resulting solvent layer containing the acrylic polymer and additives can then be thermoset to form an undercoat layer. Details of this method are described in U.S. Pat.
No. 2,383.

As mentioned above, the interfacial layer can be applied on the substrate or over the substrate, ie on the surface of the subbing layer applied on the substrate. The application of the interfacial layer is used by the conventional methods already mentioned or for depositing the surface layer.
It can be achieved by the PECVD method. In general, PECDV
Is a well known method of applying a film to a substrate from a gas discharge. For example, Kirk for plasma discharge of inorganic materials
-Othmer's Encyclopedia of Chemical Technology, 1st
It is described in Volume 0. For further details on plasma deposition of inorganic thin films, see Vosson and Kern, Thin Film Proces.
ses (Academic Press, published 1978). Examples of plasma deposition methods are U.S. Pat.Nos. 4,96,315 and 4,137,
No. 365, No. 4,361,595 and No. 4,396,641 are also described. While all of the above references generally describe plasma deposition methods, the methods disclosed herein provide polycarbonate articles with excellent wear resistance, optical properties and interlaminar adhesion. In order to do so, the various operating parameters indicated below must be followed.

The following general description of the operation of PECVD for the present invention applies to both interfacial layer and surface layer deposition. The formation of the surface layer will be described in detail later. When a discharge is initiated at low pressure in a film forming gaseous reactant, the reactant is ionized and forms a plasma. Prior to forming the film on or above the substrate, some of the material is in the form of ions, electrons and atomic free radicals generated in the plasma. Most of the reactive species consist of atomic free radicals. Although we do not wish to be bound by any particular theory, at higher prosma frequencies, such as 13.56 MHz, when free radical species diffuse from the plasma onto the deposition surface or above the substrate. It is believed that most of the film formation in the US occurs. Thus, the free radicals react on or above the primed or unprimed substrate (or on or above the interfacial layer) to form the desired layer. The obvious advantage of PECVD over conventional chemical vapor deposition is that the applied electric field promotes the formation of free radicals, thereby lowering the deposition temperature sufficiently to prevent damage to the polycarbonate substrate,
That is, it enables the use of temperatures lower than about 130 ° C. Furthermore, when using the PECVD process under the operating conditions disclosed in the present invention, it is possible to perform with a significantly higher proportion of free radicals than is possible with conventional CVD processes. PE suitable for the method disclosed in the present invention
One of the CVD device systems is Plasma Therm Inc. under the name of model 2411.
Sold by. However, in order to achieve the excellent results obtained by the present invention, this PECVD
The equipment or any other PECVD equipment must be used within the operating and compositional parameters disclosed herein.

If the interface or surface layer is to be applied by the PECVD method, the primed or unprimed substrate is placed in a reaction chamber capable of generating an electric field. The reaction chamber should be capable of being evacuated to a substantially reduced pressure, ie, to a pressure equal to or less than about 1.0 mtorr.

The method of generating and applying the electric field is not critical to this method. For example, the electric field is J. Vossen's report,
“Glow Discharge Phenomena in Plasma Etching and P
lasma Depostion ", J, Electrochemical Society, February 1979, pages 319-324.

Capacitive coupling devices can also be used to create the electric field, which is preferred for use in the present invention. According to this method, generally described in the Vosson article cited above, two electrodes are placed in the reaction chamber and a plasma is formed between these electrodes. Each electrode can be a plate of material that is a good electrical conductor, such as aluminum. Each of these electrodes preferably has a plane parallel to the other electrode.

In a preferred embodiment of the method of the invention which utilizes a capacitive coupling device, the electrodes are arranged horizontally, i.e. the upper electrode is arranged in the upper region of the reaction chamber, the flat surface of the electrode being the vacuum. It faces the flat surface of the lower electrode arranged in the lower region of the reaction chamber. The spacing between the electrodes is related to the desired strength of the applied electric field and the dimensions of the article to be coated. The interrelationship of these operating variables will be apparent to those skilled in the vapor deposition art, and thus one of skill in the art may adjust these variables for each particular use of the present invention without requiring undue experimentation. . In a preferred embodiment, the substrate is arranged on the surface of the lower electrode facing the upper electrode such that the surface of the substrate to be coated is parallel to the facing surface of the upper electrode. It will be apparent to those skilled in the art that, as an alternative, the electrodes can be arranged vertically in the reaction chamber or along other geometric planes, so long as a plasma can be generated between the electrodes.

The film-forming substance must be in vapor or gas form for use in the PECVD process. Vapor-type reactants such as acrylic or organosilicone monomers are vaporized from the liquid state before introduction into the reaction chamber.

In a preferred embodiment, the liquid substance is cooled and then degassed by applying a vacuum thereto, the liquid being then, depending on its individual boiling point, sufficiently positive to flow through a channel system such as the system described below. Heat to ambient temperature or higher to give a vapor pressure of. Alternatively, a carrier gas such as helium may be bubbled into the liquid to obtain a diluted vapor mixture with the desired composition.

Gaseous reactants such as silane or nitrous oxide are normally suitable for reaction in the plasma, but in some cases they may be stored beforehand alone or in liquid form with a carrier gas into a reaction chamber. Secure weighing.

The reaction chamber is evacuated before introducing the gaseous reactants. The reaction chamber pressure required for the process of the present invention ranges from about 50 mtorr to about 10 torr, with a preferred pressure of about 0.3 when the interfacial layer is applied.
Torr to about 0.6 torr, with a surface layer of about 1.0 torr.

The gaseous reactants forming the coating composition of the present invention can be fed into the reaction chamber away from a series of inlet tubes from an external source. The details of techniques for introducing various gases into the reaction chamber are well known in the art and need not be discussed at length here. For example, each gas inlet pipe is connected to a central supply pipe that introduces all gases into the reaction chamber. In a preferred embodiment, the gaseous reactant for the surface layer is mixed with a carrier gas such as helium to improve the flow of the reactant into the reaction chamber. The flow rates of the carrier gas and the reactant gas into the reactor are well known to those skilled in the art and can be controlled by mass flow control valves which serve both to measure the flow rate of the gas and to control such flow rate. Furthermore, if a carrier gas is used, it may be premixed with the gaseous reactants or may be fed into the central feed pipe by means of a separate inlet pipe. For example, when silane (SiH ₄ ) is used as a reaction agent for forming silicon dioxide, it can be mixed in advance so that the volume ratio of helium and SiH ₄ : He is in the range of about 2:98 to 20:80. . Although a carrier gas is not essential according to the invention, its use improves the plasma density and gas pressure uniformity within the reaction chamber. Furthermore, the use of carrier gas tends to prevent vapor phase granulation of the coating material formed by the plasma and improve the quality of the film for transparency and abrasion resistance.

If a capacitive coupling device is used, the gaseous reactants entering the reactor from the central feed valve pass between the upper and lower electrodes and on the substrate to be coated. The quality of the coating on the substrate, subbing layer or interfacial layer is largely dependent on both the flow rate and the flow dynamics of the reactants, i.e. the laminar flow properties, as described below. For example, the use of excessive flow rates causes the active film-forming reaction to react and pass the zone over the deposition surface before the reactants form a coating on the deposition surface. Conversely, if the flow rate is too low, the film forming reactant will be quickly depleted, thus resulting in a non-uniform film thickness. The flow rate of the interface layer reactant such as acrylic or organosilicone monomer is about 5 sccm to about 250 sccm.
Can range from about 20 sccm to about 100 sccm is preferred. Higher flow rates for coated surfaces larger than about 10 square feet, which may require larger reaction chambers than the Plasma Therm reactor described below.
Flow rates of up to about 2000 sccm may be required, for example. The flow rate of the reactants forming the wear resistant surface layer is about 500 sccm to about 10, for each reactant when a carrier gas is used.
It is in the range of 000 sccm, while in the absence of carrier gas it is in the range of about 5 sccm to about 500 sccm. One of ordinary skill in the art could readily select an appropriate flow rate for a particular coating material according to the teachings herein.

Laminar flow of the gaseous reactants to the deposition surface increases coating uniformity for properties such as coating thickness and hardness, transparency and for the interfacial layer and adhesion and thermal expansion compensation, which is very important to the present invention. It's important.

As used herein, the term "laminar flow" refers to a smooth and steady flow, ie, a substantially streamlined flow of gaseous reactants to a substrate and the absence of turbulent reactant molecules. Defined as a stream to be characterized. This type of gas flow is described, for example, by F. White in "Fluid Mechanics" (1979 McGraw Hi
ll Book Company), pp. 305-. Laminar flow is generally about 1 as described in this White article.
Characterized by indicating the number of Reynolds in the range of up to 1000. In a preferred embodiment of the present invention, a particularly preferred Reynolds number is about 2.5. It will be apparent to those skilled in the art that small turbulent zones may be present, but they will not appreciably affect the properties of the deposited coating. Further, as pointed out above, the mass flow of each gas may be regulated by a regulation means for controlling the laminar flow characteristics of the gaseous reactants.

In a preferred embodiment, during the plasma deposition step, the coated surface is exposed to a temperature in the range of about 100 ° to 130 ° C, preferably 100 ° C.
Heat to ℃. This heating can be accomplished by various known methods. Heat may be imparted to the coated surface through the substrate by heating, for example, by heating the lower electrode upon which the substrate rests by resistive heating. In some embodiments of the invention, the use of a coating surface temperature of 100 ° C. or higher increases the deposition rate of the upper layer material onto the lower surface, whether the polycarbonate layer or the interfacial layer, and It produces the desired compressive stress in the surface layer. Moreover, the use of this elevated temperature may increase the wear resistance of the deposited surface layer. However, the use of higher temperatures within this range is either detrimental to the quality of the interfacial layer or causes stress between the surface layer and the substrate after cooling the coated article to room temperature. Should be avoided. It should also be understood that deposition on coated surfaces maintained at temperatures between about room temperature and 100 ° C is also within the scope of the present method.

In a preferred embodiment of the present invention, the substrate surface may be cleaned by washing with an alcohol solvent such as isopropanol before applying the next layer. This step removes additives such as dust, contaminants and wetting agents from the surface. The subbing layer surface and the interfacial layer surface can also be cleaned in this way.

After washing, the substrate can be vacuum dried by known methods to completely remove the moisture present on or in the surface areas which interferes with the adhesion of subsequently deposited layers. This drying treatment can also be applied to the surface of these layers after applying the subbing layer and the interfacial layer to the polycarbonate substrate. Drying temperature ranges from approximately room temperature to approximately 120 ° C, approximately 80
The range of 0 ° C to about 90 ° C is preferred. Drying time is about 2 hours to about
A range of 16 hours, within this range longer times are used for lower temperatures and shorter times for higher temperatures. Furthermore, when this drying treatment is performed on the organosilicon type interface layer, generally,
The use of temperatures above 100 ° C should be avoided as it can induce microcracks in the organosilicon.

In a preferred embodiment of the present invention, the surface of the undercoat layer and the surface of the interfacial layer are charged into the reaction chamber and then etched. Etching methods are well known to those skilled in the art. An example of a preferred etching method is that the surface is about 25 ° C. in nitrogen gas alone.
This is a method of etching at about 100 ° C. Another useful etching method is to etch the surface in a mixture of carbon tetrafluoride and oxygen (containing about 8 vol% O ₂ in CF ₄ ) at about 25 ° C. to about 100 ° C., then at the same temperature. It consists of etching in nitrogen gas. Although the inventor does not wish to be bound to any particular theory, this etching method removes the top of the coated material, thereby allowing PECV
It is considered that when the method D is carried out, it produces free radical species of the substance to be applied by the PECVD method and free radical species of the surface substance to be bonded later.

If the interface layer is applied by the PECVD method and then the surface layer is applied to the interface layer in the same PECVD chamber, etching of the interface layer surface may not be necessary.

After treating the surface to be coated as described above, the electric field is introduced under preset frequency and power conditions to ionize this gas mixture and thereby generate a plasma, while introducing the reactants into the reaction chamber. Generate.
Methods of generating an electric field between electrodes are well known to those skilled in the art,
Therefore, it need not be described in detail here.
A DC electric field or an AC electric field from 50 Hz to about 10 GHz can be used. Output values range from about 10 watts to 5000 watts. A particularly suitable electric field generating means for the method of the invention is the use of a radio frequency power supply for generating and maintaining a plasma. When using such a power supply device,
A preferred working frequency is, for example, the Kubacki U.S. Pat.
It is 13.56 MHz as described in the specification of 4,096,315. The frequencies and power values used in each particular case are related in part to the particular deposition conditions required for the coating material. For example, when reacting an organosilicon monomer in a plasma, if a lower frequency and a higher output value are used within the above range, particularly if a lower reaction chamber pressure within the above range is further used. In addition, an increase in the polymerization rate and deposition rate of the organosilicon monomer is achieved.

Any gau reactant or reaction product that has not been deposited on the carrier gas and substrate surface after passing through the coated surface can be discharged from the reaction chamber via a discharge valve and then sent to a gas pump and exhaust system. Means for exhausting these excess materials from the reaction chamber are well known to those skilled in the art. If the electrodes are circular and flat as described above, the exhaust manifold may be located in the center of the lower electrode. Further, after applying the deposition layer by plasma, residual gas can be removed from the reaction chamber by a pump, as described above.

The thickness of the interfacial layer will depend in part on the intended end use of the article and its thickness can range generally from about 0.1 micron to about 6.0 microns, albeit less than the mode of application. When the interfacial layer is an organosilicon material containing dispersed colloidal silica applied by conventional methods as described above, a preferred thickness range is about 2.0.
Micron to about 6.0 microns.

After the interface layer is applied on the surface of the substrate, a wear-resistant surface layer is applied on this interface layer by the PECVD method outlined above. Non-limiting examples of suitable wear resistant materials are silicon dioxide, silicon nitride, silicon oxynitride, silicon carbide, silicon carbonitride, boron oxide, boron nitride, aluminum oxide, aluminum nitride, titanium dioxide, tantalum oxide, iron oxide. ,
Includes germanium oxide and germanium carbide. When the resulting article should be used as a sheet glass material,
A silicon dioxide surface layer is preferred because it is easily plasma deposited and its precursors are relatively inexpensive.

Gaseous reactants that can be combined to form a particular surface layer composition are delivered to the PECVD reaction chamber as described above. The various reactants which can be combined to form the surface layer of the present invention are well known to those skilled in the art. For example,
Silicon dioxide may be formed by the reaction of silane with nitrous oxide; by the reaction of silicon tetrachloride with oxygen; or by the reaction of tetraethoxysilane with oxygen.

As in the case of the deposition of organosilicon, the work variables for the deposition of the surface layer are related to the particular surface layer used, the desired coating thickness and the desired surface appearance.
The flow rate of the gaseous reactant forming the surface layer is in the range of about 50 sccm to about 10,000 sccm as described above. PECVD of surface layer
The internal pressure of the reaction chamber during the process ranges from about 50 millitorr to about 10 torr, in which case a direct or alternating electric field may be used. The AC electric field is in the range of about 50 Hz to about 10 GHz and the output is about 10
Get in the range of watts to about 5,000 watts. It will be apparent to those skilled in the art that adjustments to each of the above operating parameters may be made depending on the particular coating applied. When applying a silicon dioxide coating to a substrate coated with an organosilicon interface layer, it is generally preferred to use a moderate reaction chamber pressure, lower power and higher frequency within the ranges mentioned above. For example, the silane flow rate (2% concentration in helium) is about 2500 sccm and the N ₂ O flow rate is about 1
625 sccm, a frequency of about 13.56 MHz, a reaction chamber pressure of about 1 Torr, an output value of about 50 watts, and the substrate being heated to a temperature of about 100 ° C., A high quality, uniform silicon dioxide coating from silane and nitrous oxide on an organosilicon interfacial layer coated by PECVD or by conventional methods at approximately 500Å /
It can be formed at a deposition rate of minutes.

If abrasion resistance equivalent to Pyrex® is desired, the surface layer thickness is from about 2.0 microns to about 5.0.
It should be in the micron range. However, in general, the thickness of the surface layer applied by the method of the present invention is about
It can range from 0.025 microns to about 10.0 microns.

Additives for improving various properties of the articles of the present invention can be incorporated in either or both of the interfacial layer and the surface layer, and in the subbing layer, if present. You can also The particular additive to be utilized is related to the particular properties desired for the intended article and also to the method used to deposit the particular layer. For example, if the interfacial layer is applied on the substrate by conventional methods, a wide range of additives may be incorporated into the interfacial layer. Examples of additives include UV absorbers, antioxidants, fillers, reinforcing agents and wetting agents.

Various embodiments of the present invention may achieve the production of polycarbonate articles having a high degree of hardness and abrasion resistance comparable to glass. Furthermore, when the method according to the invention is used for the production of glazing materials with a surface layer of silicon dioxide, the resulting article is very smooth and free of fine cracks. In addition, the interfacial layer can provide a high degree of adhesion between the surface layer and the polycarbonate substrate and further control the difference in thermal expansion between the two.

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples.
However, these examples are for the purpose of illustrating the present invention and are not intended to limit the present invention in any way.

The tests used in some or all of the examples are outlined below.

Abrasion resistance was measured by a combination of two ASTM test methods. The Taber Abrasion Test, ASTM D1044, was tested with two total weight loads 1000 g evenly distributed on the theory of abrasion. 300 revolutions and / or 1000 revolutions were used as described below. The second test method is according to ASTM D1003 and used a Gardner Hazemeter Model UX10. In this test method, the light scattering rate (%) is measured before and after the test piece is subjected to a Taber abrasion tester. The lower this number, the better the wear resistance and hardness.

Light transmission was measured on a UV-Visible Spectrometer Model 330 from Perkin Elmer Corporation.

UV spectra were used to investigate the molecular structure of the deposits. The infrared spectrum measuring device was a Nicolet 7199FT-IR spectrometer.

Adhesion was measured by two methods. The first method is AS
TM D3359 is a scribed adhesion test according to the test method, using a 0.75 inch square (1.9 cm square) specimen of the test material.
A 2.0 mm square crosshatch was scribed, then 3M No. 610 adhesive tape was crimped onto the checkered surface and peeled off quickly and evenly. The amount of coating material remaining on the coupon is a measure of the adhesive properties of the coating to the underlying surface.

The second adhesion test is the “Sebastian Column Adhesion Test (Sebast
ian Post Adhesion Test) ”, an aluminum column having epoxy-coated studs at the end is attached to the surface of the test piece with an epoxy coating at or near the center of a 0.75 inch x 0.75 inch size test piece. The test piece is then placed at about 125 ° C. for about 2 minutes.
Heat for a time to cure the epoxy coating on the surface. The column is then inserted upside down into a Sebastian tester and a uniform tensile force normal to the surface of the specimen is applied until failure occurs. The tester automatically calculates and displays the force (pounds per square inch) required to pull the column away from the surface.

Weather resistance was measured using two separate tests. The first test is an immersion test in water at 65 ° C, in which a coated polycarbonate test piece is immersed in distilled water held at 65 ° C. The test was run for 7 days, during which test pieces were removed daily, dried, inspected and then tested for adhesion using the scribe adhesion test. If the test pieces passed the scribe adhesion test, they were further evaluated by the QUV accelerated weathering test. This test was conducted in a model QUV environment room manufactured by Q-Panel Company. The test piece loaded in this environmental chamber was exposed to UV light (280 nm to 350 nm; maximum 313 n at 70 ° C).
m) was exposed to a 12-hour cycle consisting of an 8-hour cycle and a 4-hour cycle at 50 ° C. and 100% relative temperature.
Every day for the first week, 1 for the second and third weeks
Twice a week and then weekly, macroscopic and microscopic examinations and scribe adhesion test measurements. It should be noted that some test pieces were subjected to immersion tests in water at 65 ° C. for longer than 7 days, while others were tested only for the QUV accelerated weathering test.

The thickness of the layer applied to the substrate by the plasma deposition method was controlled and determined by the working conditions and working time. Once the flow rate, substrate temperature, frequency and pressure of the reactant gas mixture have been determined, the thickness can be determined within a range of about ± 5% by simply selecting the processing time of the working process.

Uniformity of the applied coating thickness is evaluated from the interference color provided by the coating. Such a method is suitable for coatings having a thickness of about 0.3 micron. For larger coating thicknesses (approximately 0.4 to 10 microns), the profil meter [Sloan Dektak]
II] is used to measure coating uniformity. Small thin silicon wafers are placed in multiple locations prior to depositing the coating, and the steps removed after depositing the coating are exposed and used for thickness measurements.

The pinhole-free quality of the layer was evaluated from the barrier properties of the coating for various gases. Approximately 250Å ~ 1 for such measurement
A thickness in the range of 000Å was used. These thicknesses were typically significantly less than most of the test specimens of Example 1, but were exactly the same as those used to form the thicker surface layer at the working conditions. Therefore, the absence of pinholes can be inferred from this. Permeability was measured using a commercial instrument available from Mocon Corporation. Periodic inspection of the coating using a scanning electron microscope showed no pinholes.

Example 1 All test pieces 1 to 12 use a thermoplastic polycarbonate based on bisphenol A as a substrate. The dimensions of each substrate were typically about 4.0 inches by 4.0 inches with a thickness of either 0.125 inches or 0.25 inches. Further, in the case shown below, a disc having a diameter of 3.0 inches and a thickness of 0.125 inches was also used.

Specimens 1-10 are within the scope of the present invention, while Specimens 11-15 were used for control or comparison tests.

An acrylic interface layer was applied on the polycarbonate substrates of test pieces 1 and 2 by a conventional method. This acrylic material
It was a 50/50 weight day mixture of two thermosetting acrylic emulsions supplied by BFGoodrich, Hycar 237 and Hiker 256. The mixture was diluted with water to about 3.5% by volume. To this mixture was added 2.1% by weight of a UV blocker (2-ethylnexyl-2-cyano-3,3-diphenylacrylate) and 0.05% citric acid catalyst.
Weight% (50% solution) was added. This mixture is then further added to Poly-Solv EB, a glycol ether solvent sold by Olin Chemicals.
Diluted to 30% by volume. This last-mentioned substance was added to enhance the wettability of the interface layer to the surface. The acrylic material was applied to the substrate by dip coating and then heat cured. The final coating thickness was 0.8 micron.

Test pieces 3 to 6 are about 2% by weight of polyethylmethacrylate and an ultraviolet ray blocking agent (2,4-dihydroxybenzophenone).
Each of them was dip-coated with about 4% by weight of a thermoplastic acrylic material for forming an interface layer. The thickness of this acrylic coating after thermosetting is 0.2 micron for specimens 3 and 4,
For test pieces 5 and 6, it was 0.8 micron.

Specimens 7 and 8 contained an interfacial layer of an organosilicon material consisting of a dispersion of colloidal silica in a solution of a partial condensate of alkylsilanol, which also contained a UV blocker. The heat cured thickness of this material was about 5.0 microns.

The test pieces 9 and 10 were coated with an interface layer made of a butanol solution containing a solid content of 40% by weight of the crosslinkable acrylic composition and a flow coating. This composition contained hexadiol acrylate and trimethylolpropacytriacrylate in a 1: 1 weight ratio. The composition further contained 40 wt% solids colloidal silica functionalized with the hydrolysis product of methacryloxypropyltrimethoxysilane. The composition further comprises 2% by weight of diethoxyacetophenone as a UV initiator and Cyasorb 5411 as a UV blocker.
It contained 10% by weight of benzene sulfonate. After application of the interfacial layer, a PPG Industries company operating at a linear velocity of about 20 feet / min and using two medium pressure mercury lamps.
It was UV-cured by passing through a QC 1202 UV processor to an interface layer thickness of about 7.0 microns.

The test pieces 1 to 10 were coated with a surface layer in the reaction chamber of the plasma deposition apparatus of Plasma Therm Model 2411. Each test piece was placed on the lower electrode, that is, on the prosma generation site of the capacitive coupling plasma generator as described above. A surface layer of silicon dioxide was then applied to the interface layer by the method described below.

Silane was premixed in a volume ratio of helium to SiH ₄ : He of 2:98 and fed through the mass flow control valve into the central feed tube. Nitrous oxide was also fed through the mass flow control valve into the same central feed tube. The reactant gas mixture was then fed between the electrodes in the reaction chamber at the flow rates shown in Table 1. The following parameters for each of these test pieces were used: reaction chamber pressure, frequency value for high frequency generator, plasma power,
The substrate surface temperature and deposition rate are also shown in Table I.

Specimens 11 and 12 are control specimens outside the scope of the invention,
These are formed by depositing silicon dioxide directly on the polycarbonate substrate by the plasma-deposition method according to the method described above.

Specimen 13 is made of Pyrex® with no coating
It is a 0.125 inch thick test piece and is outside the scope of the present invention. This test piece was used to compare the article of the present invention for hardness and optical properties.

Specimen 14 is a 0.125 inch thick uncoated polycarbonate specimen.

Specimen 15 is a 0.125 inch thick polycarbonate specimen dip coated with the organosilicon composition used for specimens 7 and 8. No surface layer was applied to this test piece.

After removing the SiO ₂ -coated specimens from the reaction chamber and cooling to room temperature, they were subjected to the tests described above and shown in Table I.

The PECVD pressure was 800 mTorr for specimens 1-6, 11 and 12, 800-1000 mtorr for specimens 7 and 8, and 100 mtorr for specimens 9 and 10.

PECVD power was 80 watts for specimens 1-6, 11 and 12 and 50 watts for specimens 7-10.

The data shown for Specimens 7 and 8 are representative of data for a number of different aluminosilicon interface layer compositions.

The data shown for Specimens 9 and 10 are representative of the data for a number of Specimens with the same acrylic interfacial layer composition.

Article data shown in Table I, article formed by subjecting the PECVD method SiO ₂ layer of appropriate thickness to a substrate having a surface layer coated on the substrate with superior hardness and wear resistance Exemplifies that For example, test 4,
6,7 and 10 showed wear resistance comparable to Pyrex after 300 rotations and Taber rotation. Furthermore, test pieces 2, 6 and 8 are 1
It exhibited wear resistance comparable to Pyrex even after 000 Taber revolutions.

Specimens 2, 4, 6 and 12 as well as representative articles of Specimens 7 and 8 were tested for optical transmission. Based on the measurement of light transmittance, both the surface layer and the interface layer were completely transparent in the visible spectral range (400 nm-800 nm).

Measurement of UV transmission of SiO ₂ deposited by PECVD on the surface of Suprasil quartz demonstrated that UV transmission was indistinguishable from that of this quartz.

The refractive index measured using a Pulfrich refractometer for test pieces 6 and 12 was 1.470 for each test piece.
Is given, which indicates that the SiO ₂ is of high quality.

The refractive index was measured by ellipsometry while depositing a thinner coating of SiO ₂ (1000Å) deposited by PECVD on a silicon wafer. These measurements were typically in the range 1.469-1.472.

Regarding the test piece 11, the multiple reflection Fourier transform infrared spectrum (FT-IR) analysis performed on the SiO ₂ coating deposited on the silicon wafer in the reaction chamber during the deposition process of SiO ₂ was Si.
The spectral characteristics of O ₂ are given. Transmission FT-IR measured on the silicon wafer typically article of most specimens 7-10 having an SiO ₂ which is co析着gave the same spectrum as the spectral characteristics of SiO _2.

Refractive index and measurement of FT-IR of the test specimen 2, 4, 6 and 7 to 10 showed that the composition of the SiO ₂ surface layer is fully stoichiometric composition. Moreover, SEM measurements showed a perfectly continuous, pinhole-free structure for the surface layer.

Adhesion was measured on the test pieces 1 to 12 by the scribe adhesion test described above. The results are shown in Table II. Table II Scratch Adhesion Data for Example 1 Specimen No. Adhesion (peel rate%) 10 2 5-15 3 0 4 35-65 5 0 6 15-25 7 0-90 8 0-90 9 10-100 10 10-100 11 0 12 0 13-14-15 0 There are two reasons why the test pieces 7 to 10 showed a large change in adhesiveness. The first reason is that due to the cleaning and etching treatment of the adhesive surface of SiO ₂ on the interfacial layer and the loss of material from the interfacial layer surface during the deposition process (the material thus removed is deposited This is because it is significantly competing for the landing process). Etching was not optimal for some early tests of specimens 7 and 8. In the case of test pieces 9 and 10, it is considered that the adhesion was poor due to the incomplete removal of the solvent from the interface layer. This was corrected by completely removing the solvent before the deposition process, giving a high adhesion value (ie 10%).

The second reason is that the scribe adhesion test is a more severe test on the SiO ₂ surface than on the interface layer surface. To support this conclusion, test pieces 16 and 17 were tested by the column adhesion test described above. Each coupon was prepared by dip coating an organosilicon interface layer on a polycarbonate substrate and then plasma depositing SiO ₂ by the method used for the other coupons of Example 1. The column adhesion was measured before and after deposition of SiO ₂ . For comparison, another portion of the surface of each SiO ₂ coated specimen was tested by the scribe adhesion test.

Table III illustrates that specimens 16 and 17 both exhibited very good adhesion as measured by the column adhesion test. Table III further shows that the scribe adhesion test is SiO ₂
Demonstrating that it does not always give a reliable indication of adhesion for articles coated with.

The weather resistance (QUV) test was performed on a number of test pieces manufactured under the same or similar conditions as those of the test pieces 7 and 8.
It was conducted for a period of 4 months. Good adhesion retention and good optical properties were generally observed to confirm that excellent SiO ₂ adhesion was obtained when an interface layer was used.

Example 2 In this example, an organosilicon interfacial layer was applied to a series of polycarbonate substrates by the PECVD method and then SiO ₂ was deposited on the interfacial layer by the ECVD method.

A polycarbonate substrate having dimensions of about 4.0 inches × 4.0 inches × 0.125 inches represented by test pieces Nos. 18 to 25 was placed on the upper surface of the lower electrode of the same capacitively coupled plasma deposition apparatus as used in Example 1, respectively. It was Specimens 26 and 27 are polycarbonate substrates similar to Specimens 18-25 but without an interfacial layer and are used for control purposes.

Hexamethyldisiloxane (HMDS) monomer was fed into the reaction chamber via the valve and feed tube under the operating conditions shown in Table IV. The substrate surface was kept at a temperature of about 100 ° C. during the deposition process.

After the deposition process, each test piece was cooled and removed from the reaction chamber. The thickness of the polymerized organosilicon material measured with a profilometer is shown in Table IV, along with other relevant parameters.

Regarding the test pieces 18 to 215, the interface layer was slightly smooth and transparent, and the transmittance was 90% in the 400 nm to 800 nm region and 65% at 300 nm. Further, the variation in the thickness of each layer was within ± 10% of the average thickness of the layer.

Each interface layer is considered to have no pinholes based on SEM analysis. It should be noted that the high deposition rates used for test pieces 24 and 25 cause powder formation and deposition on the coating surface, which results in some surface defects. These defects were eliminated by the use of deposition rate and reduction or helium dilution.

The adhesion of each interface layer to the polycarbonate surface was excellent. For example, 100% adhesion was observed when using the scribe adhesion test.

Each test piece, including test pieces 26 and 27, was then individually loaded into a Plasmatherm model 2411 apparatus as described in Example 1. The test pieces 19 to 26 were etched in nitrogen at 100 ° C. The test piece 27 was etched in CF ₄ / O 2 at 100 ° C. A 2.0 μm thick surface layer of SiO ₂ (1.0 μm thick for test piece 26) was applied on the interface layer of each test piece according to the method of Example 1 and under the following conditions.

Plasma: Frequency: 13.56MHz; Output: 50 watts Flow velocity: SiH ₄ (2%) / He: 2500sccm N ₂ O: 1625secm Pressure: 1000 mtorr Deposition rate: 0.0.325μm / min Substrate surface temperature: 100 ° C After formation of the SiO ₂ layer, the abrasion resistance data and weatherability performance were measured for the article specimens 18-27 as shown in Table V. A "pass rating" for the test piece after the water immersion test indicates that no delamination or damage had occurred on the surface.

The data in Table V illustrates that the wear resistance for each of the test specimens of the present invention was acceptable. Furthermore, most of the test pieces 18 to 25 also had good weather resistance.

For all test pieces, the presence of pinholes and microcracks was not observed in the SiO ₂ surface layer.

The use of the interfacial layer provided better post water immersion adhesion than the one without the interfacial layer, ie, control specimens 26 and 27. Therefore, it is clear that the interfacial layer acts as an expansion compensation layer between the polycarbonate substrate and the SiO ₂ layer during heating and testing.

Various modifications and variations of the present invention are possible based on the above disclosure. Therefore, it is needless to say that various modifications may be made to the disclosed specific embodiments of the present invention within the intended scope of the present invention as defined in the claims.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location C23C 14/10 8414-4K 14/20 8414-4K (72) Inventor Stefan Jasek-Ruzad United States, No. 140, Appleton Road, Lexford, NY (56) References JP-A-60-29702 (JP, A)

Claims (13)

[Claims] 1. A wear resistant article comprising a polycarbonate substrate; an interfacial layer of a tacky resinous composition comprising an organosilicon material on the substrate; and an abrasion resistant surface layer on the interface layer. In the process of (a) applying the interfacial layer to the surface of the polycarbonate substrate and (b) (i) applying the interfacial layer on the surface of the polycarbonate substrate to a pressure of 50 millitorr to 10 torr. And (ii) at least one gaseous reactant capable of reacting to form the composition of said surface layer, together with a carrier gas, having a Reynolds number of about 2.5 with respect to the surface of the interfacial layer. In a laminar flow, it is fed into the reaction chamber at a flow rate in the range of 500 sccm to 10,000 sccm, during which an electric field is generated in the reaction chamber to form a plasma of the gaseous reactant, and this plasma is direct current or 50 Hz to 10 GHz. Range of Formed by a generator operating at alternating wave number and power output in the range of 10 watts to 5,000 watts, the substrate is heated to a temperature in the range of room temperature to 130 ° C., and the gaseous reactants are reacted in a plasma. A method of manufacturing an abrasion resistant article, comprising the step of forming the surface layer on the interface layer, thereby applying the abrasion resistant surface layer on the interface layer. 2. The method according to claim 1, wherein the adhesive resin composition is applied onto the substrate by a coating means. 3. The organosilicon material comprises the following components: (a) Formula RSi (O) in a mixture of aliphatic alcohol and water.
H) ₃ or R ₂ Si (OH) ₂ (wherein R is a group selected from the group consisting of an alkyl group having 1 to 3 carbon atoms and an aryl group having 6 to 20 carbon atoms) A silanol having at least 70% by weight of the silanol is CH ₃ Si.
A dispersion of colloidal silica in a solution of a partial condensate of (OH) ₃ or (CH ₃ ) ₂ Si (OH) ₂ (wherein the dispersion is 10-
50% by weight of solids, which essentially consists of 10-70% by weight of colloidal silica and 30-90% by weight of partial condensate); and (b) the formula (In the formula, X is> C = O or Y is H or OH; Z is H, OH, OQ or OW,
At least one Z is OH when Y is H; Q
It is the _{-CH 2 (CH 2) nSi (} R 2) x (OR 1) y; W is -CmH
_{2m + 1} ; x = 0, 1 or 2, y = 1, 2 or 3, x +
y = 3; R ¹ is an alkyl or alkanoyl group having ¹ to 6 carbon atoms; R ² is an alkyl group having 1 to 6 carbon atoms; n = 0, 1 or 2 and 3. A process according to claim 1 or 2 which is a further curable organopolysiloxane composition comprising an effective amount of a UV absorber comprising a compound having m = 1 to 18). 4. The process according to claim 3, wherein the organopolysiloxane composition has an alkaline pH; and the dispersion of colloidal silica is stabilized with ammonium hydroxide. 5. The method according to claim 3, wherein an undercoat layer is provided between the surface of the substrate and the interface layer. 6. The method according to claim 5, wherein the undercoat layer contains at least one ultraviolet absorber. 7. The method according to claim 6, wherein the undercoat layer is formed of an acrylic polymer. 8. The method according to claim 1, wherein the interface layer is applied to the substrate by a plasma enhanced chemical vapor deposition method. 9. The method according to claim 8, wherein an undercoat layer containing an acrylic polymer and an ultraviolet absorber is provided between the surface of the substrate and the interface layer. 10. The method of claim 8 wherein the interface layer material is formed by polymerizing organosilicon monomer vapor in plasma. 11. The method according to claim 10, wherein the organosilicon monomer is selected from the group consisting of hexamethyldisilazane, hexamethyldisiloxane, vinyltrimethylsilane and octamethylcyclotetrasiloxane. 12. The surface layer is a material selected from the group consisting of silicon carbide, silicon dioxide, silicon nitride, silicon oxynitride, boron oxide, boron nitride, aluminum oxide, aluminum nitride and titanium dioxide. The manufacturing method according to any one. 13. The surface layer is silicon dioxide and has a thickness in the range of 2.0 to 5.0 microns.
The production method according to any one of 1.